Controlling pest populations is essential to modern agriculture, food storage, and hygiene. There are more than ten thousand species of pests that cause losses in agriculture. The world-wide agricultural losses amount to billions of U.S. dollars each year. Pests, such as termites, are also known to cause damage to all kinds of private and public structures resulting in billions of U.S. dollars in losses each year. Pests also eat and adulterate stored food, resulting in billions of U.S. dollars in losses each year, as well as deprivation of food needed for people.
Certain pests have or are developing resistance to pesticides in current use. Hundreds of pest species are resistant to one or more pesticides. Accordingly, there exists a continuous need for new pesticides and for processes of forming such pesticides.
U.S. Pat. Nos. 7,678,920 and 7,687,634 describe certain pesticidal sulfoximine compounds and U.S. Pat. No. 8,188,292 describes certain pesticidal sulfilimine compounds. Some of these sulfoximine and sulfilimine compounds contain a pyridine functional group. It has now been surprisingly discovered that forms of one or more of these compounds where the pyridine functional group has been N-oxidized exhibit pesticidal properties. Pyridine N-oxides are commonly prepared from direct oxidation with peracids, such as m-chloroperoxybenzoic acid (mCPBA). For some functionalized pyridines such as 2-substituted-5-(1-alkylthio)alkyl-pyridines however, the sulfide functionality is susceptible to oxidation, so direct oxidation with mCPBA is disfavored. Accordingly, there exists a need for processes of forming such N-oxidized compounds.